Help Center/ DataArts Studio/ API Reference/ Calling APIs/ Making an API Request
Updated on 2024-11-06 GMT+08:00
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Making an API Request

This section describes the structure of a REST API request, and uses the IAM API for creating an IAM user as an example to demonstrate how to call an API. This API is used by the administrator to create an IAM user.

Request URI

A request URI is in the following format:

{URI-scheme}://{Endpoint}/{resource-path}?{query-string}

Although a request URI is included in the request header, most programming languages or frameworks require the request URI to be transmitted separately.

Table 1 URI parameters

Parameter

Description

URI-scheme

Protocol used to transmit requests. All APIs use HTTPS.

Endpoint

Domain name or IP address of the server bearing the REST service endpoint. The endpoint varies between services in different regions.

An endpoint is the request address for calling an API. Endpoints vary depending on services and regions. You can obtain endpoints of the service from Endpoints.

For example, the endpoint of IAM in region CN-Hong Kong is iam.ap-southeast-1.myhuaweicloud.com.

resource-path

Access path of an API for performing a specified operation. Obtain the value from the URI of an API. For example, resource-path of the API used to create an IAM user is /v3.0/OS-USER/users.

query-string

Query parameter, which is optional. Ensure that a question mark (?) is included before each query parameter that is in the format of "Parameter name=Parameter value", for example, ?limit=10, it indicates that a maximum of 10 data records are allowed.
For example, if you want to create an IAM user, combine the endpoint of any region (for example, iam.ap-southeast-1.myhuaweicloud.com for CN-Hong Kong) with the resource-path (/v3.0/OS-USER/users) in the URI of the API used to create an IAM user. The following is an example: 
https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users
Figure 1 Example URI

To simplify the URI display in this document, each API is provided only with a resource-path and a request method. The URI-scheme value of all APIs is HTTPS, and the endpoints of all APIs in the same region are identical.

Request Method

The HTTP protocol defines the following request methods that can be used to send a request to the server:
Table 2 HTTP methods

Method

Description

GET

Requests the server to return specified resources.

PUT

Requests the server to update specified resources.

POST

Requests the server to add resources or perform special operations.

DELETE

Requests the server to delete specified resources, for example, an object.

HEAD

Same as GET except that the server must return only the response header.

PATCH

Requests the server to update partial content of a specified resource.

If the resource does not exist, a new resource will be created.
For example, in the URI of the IAM API for creating an IAM user, the request method is POST. An example request is as follows: 
POST https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users

Request Header

You can also add additional header fields to a request, such as the fields required by a specified URI or HTTP method. For example, to request the authentication information, add Content-Type, which specifies the request body type.

Table 3 lists common request header fields.
Table 3 Common request header fields

Field

Description

Mandatory

Example

Content-Type

Request body type or format. Its default value is application/json.

Yes

application/json

Content-Length

Specifies the length of the request body. The unit is byte.

No

3495

X-Language

Request language

No

en_us

X-Auth-Token

Specifies a user token. The user token is the value returned by the API used to obtain a user token. This API is the only API that does not require authentication.

The token is the value of X-Subject-Token in the response header.

This field is mandatory for token authentication.

The following is part of an example token:

MIIPAgYJKoZIhvcNAQcCo...ggg1BBIINPXsidG9rZ

Authorization

Authentication information.

When AK/SK authentication is enabled, this field is automatically specified when SDK is used to sign the request.

This field is mandatory for AK/SK-based authentication.

None

X-Sdk-Date

Time when the request is sent. The format is YYYYMMDD'T'HHMMSS'Z'. The value is the current GMT time of the system.

When AK/SK authentication is enabled, this field is automatically specified when SDK is used to sign the request.

This field is mandatory for AK/SK-based authentication.

20150907T101459Z

Host

Specifies the server domain name and port number of the resources being requested. The value can be obtained from the URL of the service API. The value is in the format of hostname[:port]. If the port number is not specified, the default port is used. The default port number for HTTPS is 443.

This field is mandatory for AK/SK-based authentication.

code.test.com

or

code.test.com:443

X-Project-Id

Subproject ID. Obtain the project ID by following the instructions in Project ID and Account ID.

This field is mandatory for calling service APIs that use AK/SK authentication in subprojects.

e9993fc787d94b6c886cbaa340f9c0f4

X-Domain-ID

Domain ID. Obtain the domain ID by following the instructions in Project ID and Account ID.

This field is mandatory for calling global APIs that use AK/SK authentication.

0a2f5e28af00f3850f31c00f31e884e0

workspace

Workspace ID. For details about how to obtain it, see Instance ID and Workspace ID.
  • You do not need to set this field when calling a CDM or DIS API.
  • This field is mandatory when there are multiple DataArts Studio instances during a call to a DataArts Factory API.

    This field is optional when there is only one DataArts instance. This field is optional when there is only one DataArts Studio instance. If this field is not specified, data in the default workspace is queried by default. To query data in other workspaces, include this field in the request header.

  • This header is mandatory for calling the APIs of other modules. Otherwise, API calls will fail.

d1cd7861478748a6925bc02f47c69279

X-Dlm-Type

DataArts DataService edition, which is Exclusive

This parameter is mandatory for calling DataArts DataService APIs.

EXCLUSIVE: exclusive edition

In addition to supporting token-based authentication, APIs also support authentication using access key ID/secret access key (AK/SK). During AK/SK-based authentication, an SDK is used to sign the request, and the Authorization (signature authentication) and X-Sdk-Date (time when the request is sent) header fields are automatically added to the request.

For more information, see "AK/SK-based Authentication" in Authentication.

The following is an example request of the API that is used to create an IAM user and that uses AK/SK authentication: 
POST https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users
Content-Type: application/json
X-Sdk-Date: 20240416T095341Z
Authorization: SDK-HMAC-SHA256 Access=****************, SignedHeaders=content-type;host;x-sdk-date, Signature=****************

Request Body

The body of a request is often sent in a structured format (for example, JSON or XML) as specified in the Content-Type header field. The request body transfers content except the request header. If the request body contains Chinese characters, these characters must be coded in UTF-8.

The request body varies between APIs. Some APIs do not require the request body, such as the APIs requested using the GET and DELETE methods.

For the API used to obtain an IAM user, you can obtain the request parameters and their descriptions from the API request. The following provides an example request with a body included. Replace the italic fields in bold with the actual values.
  • accountid indicates the ID of the account to which the IAM user belongs.
  • username indicates the IAM username to be created.
  • email indicates the email address of the IAM user.
  • ********** indicates the login password of the IAM user.
POST https://iam.ap-southeast-1.myhuaweicloud.com/v3.0/OS-USER/users
Content-Type: application/json
X-Sdk-Date: 20240416T095341Z
Authorization: SDK-HMAC-SHA256 Access=****************, SignedHeaders=content-type;host;x-sdk-date, Signature=****************

{
     "user": {
         "domain_id": "accountid",
         "name": "username",
         "password": "**********",
         "email": "email",
         "description": "IAM User Description"
     }
 }

If all data required for the API request is available, you can send the request to call the API through curl, Postman, or coding.

Parent Topic: Calling APIs